This invention relates to a device and method for controlling pests in animals, especially livestock and poultry.
A longstanding problem that has plagued the livestock and poultry industries is the existence of ectoparasitic and disease-carrying pests such as face flies, stable flies, horn flies, Gulf Coast ticks, Spinose ear ticks, fleas, mites, chiggers, and screw worms. Other types of pests, namely predators such as coyotes, foxes, cougars, bobcats, etc., have been troublesome as well. Numerous attempts have been made to control such pests, but all have practical or economic disadvantages. For example, sprays, dusts and dips have been used for some time with varying degrees of success, but application is often labor intensive and protection is usually of short duration.
Livestock eartags comprising a composite polymer with pesticide or repellent dispersed thereon or therein are known. See, for example, U.S. Pat. Nos. 3,756,200, 3,942,480, 3,949,708, 4,059,074, and 4,195,075. However, such devices suffer from various disadvantages, such as not being reusable; of having a release rate which is nonzero order or declining over time, nonadjustable and of relatively short duration; of insufficient tensile and ductile strength which contributes to brittleness, thus causing loss through breakage; and, in some cases, toxicity to the livestock. Further, nonzero order or a declining rate of release over time is wasteful and often allows target insecttype pests to develop immunity to the pesticide.
Eartags with replaceable active ingredient dispensers are also known. See, for example, U.S. Pat. No. 4,366,777 which discloses a dispenser comprising a strip of polymeric tape with either an activeingredient-soaked wick or an active-ingredient-impregnated polymeric layer attached thereto, the strip capable of encircling the neck portion of an eartag and either adhering to itself by pressure-sensitive adhesive or threading through itself in the same manner as a garbage-bag-style tie. The wick may be a fibrous sleave soaked by a crushable ampoule containing the active ingredient. However, such dispensers suffer from some of the same drawbacks as other prior art attempts at pest control, i.e., having a release rate which is non-zero order, nonadjustable, and of relatively short duration.
There is therefore a need for a pest control which is effective and inexpensive, durable, reusable, adjustable, and has a long-term zero-order release rate of pesticide or repellent. These needs and others have been met by the novel device and method of the present invention, which are summarized and particularly described below.